dbcve.org
Memory Buffer Bounds ErrorWeakness · CWE-119

CVE-2023-31364

HIGH · 8.3 CVSS v4.0 Published 2026-02-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
89/100
Remediation priority · High
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Improper handling of direct memory writes in the input-output memory management unit could allow a malicious guest virtual machine (VM) to flood a host with writes, potentially causing a fatal machine check error resulting in denial of service.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A vulnerability in the IOMMU (Input-Output Memory Management Unit) allows a malicious guest VM to flood the host with direct memory writes, causing a fatal machine check error (MCE) and resulting in host denial of service.

MitigationApply vendor-provided patches to the hypervisor or firmware containing IOMMU fixes. Consider restricting direct device assignment to untrusted VMs and ensuring IOMMU is properly configured with appropriate bounce buffering or memory protection limits.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify IOMMU is enabled in the system
    Check system firmware (BIOS/UEFI) settings for Intel VT-d or AMD-Vi (IOMMU) configuration, or run 'dmesg | grep -i iommu' on Linux hosts to see if IOMMU is active at boot.
    Affected if IOMMU is enabled - this is a prerequisite for the vulnerability to be exploitable; if IOMMU is disabled, the specific attack surface may not exist.
  2. Identify the hypervisor and version in use
    Run commands such as 'xl info' (Xen), 'virsh version' (KVM/libvirt), 'vmware -v' (VMware), or check Hyper-V host information to determine the hypervisor type and version.
    Affected if The hypervisor version falls within any vendor-specific affected range (check respective vendor advisories for CVE-2023-31364).
  3. Confirm IOMMU is exposed to guest VMs
    Check hypervisor configuration files or settings to determine whether IOMMU/direct memory access (DMA) is being passed through to any VMs, particularly untrusted or third-party VMs.
    Affected if Untrusted VMs have direct IOMMU passthrough or SR-IOV device assignment enabled, allowing them to perform DMA operations.
  4. Check host system logs for machine check errors
    Review system logs (Linux: 'dmesg' or /var/log/messages, VMware: vmware.log, Xen: /var/log/xen/dom0.log) for Machine Check Exception (MCE), PCI errors, or IOMMU fault messages.
    Affected if Recent MCE errors or IOMMU fault events are present, which may indicate exploitation attempts or successful abuse.
  5. Audit VM configuration for excessive DMA permissions
    Inspect VM definition files (e.g., XML for libvirt, .vmx for VMware, .cfg for Xen) for any 'passthrough' or 'iommu' settings that grant guests direct hardware access without isolation.
    Affected if VMs are configured with direct hardware passthrough or IOMMU group isolation is not enforced.

You are affected if your system has IOMMU enabled and exposes it to guest VMs, and your hypervisor version matches a vendor-advisory affected range for CVE-2023-31364, or you observe unexplained MCE errors suggesting possible exploitation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-provided patches to the hypervisor or firmware containing IOMMU fixes. Consider restricting direct device assignment to untrusted VMs and ensuring IOMMU is properly configured with appropriate bounce buffering or memory protection limits.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-31364 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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